The drag of the rear facing surfaces of a car (base drag) can account for upwards of 30% of the total drag. ‘Boat tailing’ (a progressive reduction in vehicle width (Y) and/or height (Z) along a longitudinal axis (X) towards the rear of the vehicle) has been a historic countermeasure. This promotes base pressure recovery, reducing drag. However, aesthetic and packaging considerations limit its applicability in automotive design.
US20110000727 discloses air inlet openings formed in vertical fins extending from the longitudinal roof members. The air inlet openings direct air over an outer skin of a rear deck lid and onto a rear air deflection device.
US20120104800 discloses a vehicle having an opening formed between lateral end sections of the windshield and the adjacent A-pillars. The air flows through this gap-shaped opening when the vehicle is moving. This reduces the formation of high loss vortices in the lateral area of the vehicle.
EP2572966A1 discloses providing a protrusion at the rear of the vehicle to drawing air from inside the vehicle into the external flow, suppressing vortex formation. EP1098809B1 discloses the use of ‘base bleed’. U.S. Pat. No. 7,886,859 discloses directing air entrained for the purposes of cooling for the purpose of drag reduction.
It is against this backdrop that the present invention has been conceived. At least in certain embodiments, the present invention seeks to overcome or ameliorate at least some of the shortcomings associated with the prior art arrangements.